1. Field of the Invention
The present invention relates to a method for monitoring bacterial overgrowth of the small intestine. More specifically, the invention relates to administering labeled sorbitol or sorbitol derivatives to an individual and assessing labeled carbon dioxide in one or more specimens from the individual to determine bacterial overgrowth of the small intestine.
2. Description of the Prior Art
Normally, the human small intestine contains only small amounts of bacteria compared to the colon. Many structural or functional disorders of the gastrointestinal tract can lead to bacterial overgrowth of the small intestine. Small bowel bacterial overgrowth is characterized by steatorrhea (fat malabsorption), diarrhea, vitamin deficiencies, and carbohydrate malabsorption. Optimum care of patients with bacterial overgrowth requires adequate evaluation and proper antibiotic therapy. Unfortunately, bacterial overgrowth is difficult to diagnose with accuracy. Unlike many other illnesses, bacterial overgrowth is never cured but requires constant monitoring and therapy.
The current diagnostic "gold standard" for identifying small intestinal bacterial overgrowth is a quantitative culture of small bowel fluid aspirate. Jejunal fluid is collected through a small tube that is swallowed by the patient and positioned by a physician under fluoroscopic (x-ray) guidance. The jejunal fluid aspiration is cultured for the presence of bacteria. There are many limitations to this technique as a diagnostic test of small bowel bacterial overgrowth. These limitations include (1) discomfort of placing orointestinal tubes, (2) exposure to x-rays, (3) high medical costs (about $700) (4) culturing the aspirate is time consuming and (5) the poor diagnostic sensitivity of single aspirations.
The need for a reliable screening test for bacterial overgrowth fostered the development of non-invasive breath tests. These tests utilized radioactive .sup.14 C and nonradioactive .sup.13 C substrates, such as cholyl-[.sup.14 C]-glycine (bile acid breath test) and .sup.14 C and .sup.13 C-xylose, or relied on bacterial metabolism of glucose or lactulose to evolve hydrogen gas in the breath. With the exception of the xylose breath test, all the other non-invasive screening tests have been shown to be unreliable to screen for bacterial overgrowth because of poor sensitivity and specificity of these tests. Recent clinical experience with the xylose breath test, however, has suggested a decrease in the sensitivity and specificity, perhaps due to the altered ability of intestinal bacteria to metabolize xylose.
These and other disadvantages of the prior art are overcome by the present invention. As shown herein, we provide a novel test for assessing bacterial overgrowth of the small intestine.